Some features of competent streptococci

1972 ◽  
Vol 18 (4) ◽  
pp. 487-491 ◽  
Author(s):  
R. Pakula ◽  
L. R. Spencer
Keyword(s):  
Cell Proliferation ◽  
Dna Synthesis ◽  
Deoxyribonucleic Acid ◽  
Competence Development ◽  
Dna Uptake ◽  
Related Strain ◽  
Competent Cells ◽  
Insoluble Material ◽  
Competence Factor

The Wicky Streptococcus was rendered competent for deoxyribonucleic acid (DNA) uptake with the competence factor (CF) derived from a related strain. Initiation of competence resulted in an almost immediate decline of the rate of cell proliferation and of incorporation of 14C-uracil into acid-insoluble material. DNA synthesis was affected in the later stage of competence development. The competent cells were penicillin resistant.

THE EFFECT OF "COMPETASE" ON DNA UPTAKE IN PROVOKED TRANSFORMATION OF A STREPTOCOCCUS

1965 ◽  
Vol 11 (5) ◽  
pp. 823-827 ◽  
Author(s):  
R. Pakula ◽  
A. H. W. Hauschild
Keyword(s):  
Deoxyribonucleic Acid ◽  
Brain Heart Infusion ◽  
Streptomycin Resistance ◽  
Brain Heart Infusion Broth ◽  
Dna Uptake ◽  
Retarding Effect ◽  
Competence Factor ◽  
Effect On Growth

The competence-provoking factor produced by the highly transformable group H streptococcus, strain Challis, was used to provoke efficient transformability in the poorly transformable group H streptococcus, strain Wicky. Transformations to streptomycin resistance were carried out with C14-labelled DNA which was extracted from bacteria fed with thymidine-2-C14.When cultures of strain Wicky were grown in Difco brain–heart infusion broth, supplemented with serum, and treated with competence factor and deoxyribonucleic acid, 25 to 40% of viable units were transformed while no transformation occurred without the factor. At the same time, the incorporation of C14 into cells treated with competence factor was higher than incorporation of C14 into untreated cells.Crude preparations of the competence factor had a retarding effect on growth of the streptococcus, irrespective of whether DNA was added.

scholarly journals Competence for Deoxyribonucleic Acid Uptake and Deoxyribonuclease Action External to Cells in the Genetic Transformation of Diplococcus pneumoniae

1973 ◽  
Vol 114 (1) ◽  
pp. 152-163 ◽  
Author(s):  
S. Lacks ◽  
B. Greenberg
Keyword(s):  
Protein Synthesis ◽  
Genetic Transformation ◽  
Deoxyribonucleic Acid ◽  
Acid Uptake ◽  
Dna Uptake ◽  
Temperature Dependent ◽  
Competent Cells ◽  
Wild Strains

A mutant of Diplococcus pneumoniae that apparently does not require activator can become competent for uptake of deoxyribonucleic acid (DNA) when grown in dilute cultures or in the presence of trypsin. Development of competence in both mutant and wild strains is temperature dependent, being 10-fold greater at 30 C than at 37 C. Induction of competence on a shift from 37 to 30 C requires protein synthesis and the presence of Mg 2+ and Ca 2+ ; uptake of DNA does not require protein synthesis. Competence decays exponentially at higher temperatures. As well as taking up DNA, competent cells release oligonucleotide fragments of donor DNA in the medium external to the cells. Normal strains release fragments comparable in amount to the DNA taken up; but, in a mutant selected for inability to degrade DNA in agar, the amount of fragments formed external to the cells is only 40% of DNA uptake. Requirements for external deoxyribonuclease action are identical to those for DNA uptake: prior development of competence and the presence during treatment with DNA of Mg 2+ ions and a source of energy.

Some characteristics of streptococci competent for uptake of deoxyribonucleic acid

1970 ◽  
Vol 16 (5) ◽  
pp. 345-350 ◽  
Author(s):  
R. Pakula ◽  
P. Ray ◽  
L. R. Spencer
Keyword(s):  
Methylene Blue ◽  
Deoxyribonucleic Acid ◽  
Dna Uptake ◽  
Competent Cells ◽  
Characteristic Features

The degree of competence for uptake of deoxyribonucleic acid (DNA uptake) of the Challis streptococcus was found to be strictly related to the concentration of cell-bound competence-provoking factor (CPF). Antibodies against competent cells and antibodies against crude concentrates of CPF inhibited DNA uptake by competent cells. Both types of antibodies interacted also with soluble CPF and reduced its capacity to induce competence. Two characteristic features of competent streptococci were revealed: high precipitability at low pH's and a reduced capacity to absorb methylene blue.

Genotoxicity and Cell Proliferative Activity of 3-Chloro-4-(Dichloromethyl)-5-Hydroxy-2(5H)-Furanone [MX] in Rat Glandular Stomach

1992 ◽  
Vol 25 (11) ◽  
pp. 341-345 ◽  
Author(s):  
C. Furihata ◽  
M. Yamashita ◽  
N. Kinae ◽  
T. Matsushima
Keyword(s):  
Cell Proliferation ◽  
Body Weight ◽  
Dna Synthesis ◽  
Ornithine Decarboxylase ◽  
Tap Water ◽  
Fold Increase ◽  
Single Strand ◽  
Glandular Stomach ◽  
Decarboxylase Activity ◽  
Pyloric Mucosa

MX is a strong direct acting mutagen on Salmonella typhimurium TA100 and is present in chlorinated tap water which contains organic compounds. MX was administered orally to 7-week-old male F344 rats, and its geno-toxicity in the pyloric mucosa of stomach was examined by analysis of DNA single strand scissions by the alkaline elution method. The effect of MX on cell proliferation was examined by assays of the inductions of replicative DNA synthesis and ornithine decarboxylase. MX at closes of 20-48 mg/kg body weight induced DNA single strand scissions dose-dependently (p<0.02) in the pyloric mucosa of the stomach 2 h after its administration. Moreover at doses of 10-60 mg/kg body weight, it induced up to 21-fold increase in replicative DNA synthesis (p<0.01) 16 h after its administration. At doses of 10-60 mg/kg body weight, it induced up to 100-fold increase in ornithine decarboxylase activity with a maximum 16 h after its administration. These results suggest that MX is genotoxic and induces cell proliferation in the glandular stomach of rats.

scholarly journals Involvement of deoxyribonucleic acid polymerase β in nuclear deoxyribonucleic acid synthesis

1978 ◽  
Vol 173 (1) ◽  
pp. 309-314 ◽  
Author(s):  
T R Butt ◽  
W M Wood ◽  
E L McKay ◽  
R L P Adams
Keyword(s):  
Dna Synthesis ◽  
Dna Polymerase ◽  
Deoxyribonucleic Acid ◽  
Nuclear Dna ◽  
Dna Polymerase Beta ◽  
Cell Nuclei ◽  
High Molecular Weight Dna ◽  
Dna Polymerase Alpha ◽  
Polymerase Beta

The effects on DNA synthesis in vitro in mouse L929-cell nuclei of differential extraction of DNA polymerases alpha and beta were studied. Removal of all measurable DNA polymerase alpha and 20% of DNA polymerase beta leads to a 40% fall in the replicative DNA synthesis. Removal of 70% of DNA polymerase beta inhibits replicative synthesis by 80%. In all cases the nuclear DNA synthesis is sensitive to N-ethylmaleimide and aCTP (arabinosylcytosine triphosphate), though less so than DNA polymerase alpha. Addition of deoxyribonuclease I to the nuclear incubation leads to synthesis of high-molecular-weight DNA in a repair reaction. This occurs equally in nuclei from non-growing or S-phase cells. The former nuclei lack DNA polymerase alpha and the reaction reflects the sensitivity of DNA polymerase beta to inhibiton by N-ethylmaleimide and aCTP.

scholarly journals A MYBL2 complex for RRM2 transactivation and the synthetic effect of MYBL2 knockdown with WEE1 inhibition against colorectal cancer

2021 ◽  
Vol 12 (7) ◽  
Author(s):  
Qian Liu ◽  
Lijuan Guo ◽  
Hongyan Qi ◽  
Meng Lou ◽  
Rui Wang ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cell Proliferation ◽  
Dna Synthesis ◽  
Ectopic Expression ◽  
Building Blocks ◽  
Small Subunit ◽  
S Phase ◽  
Clinical Samples ◽  
Dependent Manner

AbstractRibonucleotide reductase (RR) is a unique enzyme for the reduction of NDPs to dNDPs, the building blocks for DNA synthesis and thus essential for cell proliferation. Pan-cancer profiling studies showed that RRM2, the small subunit M2 of RR, is abnormally overexpressed in multiple types of cancers; however, the underlying regulatory mechanisms in cancers are still unclear. In this study, through searching in cancer-omics databases and immunohistochemistry validation with clinical samples, we showed that the expression of MYBL2, a key oncogenic transcriptional factor, was significantly upregulated correlatively with RRM2 in colorectal cancer (CRC). Ectopic expression and knockdown experiments indicated that MYBL2 was essential for CRC cell proliferation, DNA synthesis, and cell cycle progression in an RRM2-dependent manner. Mechanistically, MYBL2 directly bound to the promoter of RRM2 gene and promoted its transcription during S-phase together with TAF15 and MuvB components. Notably, knockdown of MYBL2 sensitized CRC cells to treatment with MK-1775, a clinical trial drug for inhibition of WEE1, which is involved in a degradation pathway of RRM2. Finally, mouse xenograft experiments showed that the combined suppression of MYBL2 and WEE1 synergistically inhibited CRC growth with a low systemic toxicity in vivo. Therefore, we propose a new regulatory mechanism for RRM2 transcription for CRC proliferation, in which MYBL2 functions by constituting a dynamic S-phase transcription complex following the G1/early S-phase E2Fs complex. Doubly targeting the transcription and degradation machines of RRM2 could produce a synthetic inhibitory effect on RRM2 level with a novel potential for CRC treatment.

DEOXYCYTIDYLATE DEAMINASE LEVELS IN REGENERATING RAT LIVER

1961 ◽  
Vol 39 (6) ◽  
pp. 1043-1054 ◽  
Author(s):  
D. K. Myers ◽  
C. Anne Hemphill ◽  
Constance M. Townsend
Keyword(s):  
Dna Synthesis ◽  
Liver Regeneration ◽  
Partial Hepatectomy ◽  
Rat Liver ◽  
Deoxyribonucleic Acid ◽  
Regenerating Liver ◽  
Regenerating Rat Liver ◽  
High Level ◽  
Early Regeneration

Deoxycytidylate deaminase activity and net synthesis of deoxyribonucleic acid (DNA) in vivo were found to increase at approximately the same time during the early stages of liver regeneration. However, deaminase activity in the regenerating liver remained at a high level for 1 day after DNA synthesis had slowed down again during the later stages of regeneration. The increase in deaminase activity was restricted as a result of exposure to 600 r X radiation during early regeneration, but this effect only became evident 11–16 hours after the irradiation. Irradiation on the second day after partial hepatectomy, when deaminase levels in control regenerating livers were relatively constant, failed to affect the deaminase activity immediately but did produce a 40–50% decrease in activity 11–16 hours later. Other antimitotic agents, e.g., colchicine, had little effect on deaminase activity.

Selective inhibition of cell proliferation and DNA synthesis by the polysulphated carbohydrate ι-carrageenan

1995 ◽  
Vol 36 (4) ◽  
pp. 325-334 ◽  
Author(s):  
Richard Hoffman ◽  
Walter Woodrow Burns ◽  
Dietrich H. Paper
Keyword(s):  
Cell Proliferation ◽  
Dna Synthesis ◽  
Selective Inhibition

IN VIVO SYNTHESIS AND BREAKDOWN OF DEOXYRIBONUCLEIC ACID IN TRIBOLIUM CONFUSUM DUVAL

1966 ◽  
Vol 44 (12) ◽  
pp. 1571-1575 ◽  
Author(s):  
K. D. Chaudhary ◽  
A. Lemonde
Keyword(s):  
Dna Synthesis ◽  
Growth Phase ◽  
Deoxyribonucleic Acid ◽  
Total Concentration ◽  
Larval Growth ◽  
Pupal Stage ◽  
Larval Period ◽  
Tribolium Confusum ◽  
In Vivo Synthesis

The in vivo synthesis of deoxyribonucleic acid (DNA), as shown by the rate of incorporation of14C-thymidine, has been investigated at different stages in the life cycle of Tribolium confusum. During the larval period, a close similarity is observed between the rate of DNA synthesis and the pattern of growth. The pupal stage, which is a non-growth phase, is characterized by a cessation of DNA synthesis. During the larval growth phase, although the 3-day-old larvae have the lowest and the 13-day-old have the highest rate of DNA synthesis, the rate of DNA degradation in the older larvae is almost twice as great as that of the younger larvae. These findings are consistent with the observed total concentration of DNA of the insect at these stages.

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